Heat exchangers are often used as automobile oil coolers for maintaining the viscosity characteristics of the oil as it circulates throughout the engine components. U.S. Pat. No. 4,324,213 to Kasting et al, issued Apr. 13, 1982 and U.S. Pat. No. 4,821,795 to applicant, issued Apr. 18, 1989 disclose heat exchangers used for cooling the oil in an automotive engine. The oil coolers generally include a tank having a hot fluid inlet and outlet and integral cap members closing each end of the tank and providing a cooling fluid inlet and outlet. The hot fluid and cooling fluid inlets and outlets are connected to corresponding rigid couplers on the engine housing. The cap members are fixedly connected to the ends of the tank, such as by a weld, to prevent relative movement therebetween. As can be appreciated, a slight offset in the orientation angle of the cap inlet and outlet in relation to the tank inlet and outlet would make for difficult assembly to the engine housing. Upon connection to the housing, the offset in the orientation angle could cause stress and fatigue to the oil cooler and/or engine housing and result in failure of the oil cooler.
Various methods have been employed to provide a rotational connection between the tank and the cap members to allow for adjustment of the orientation angle between the hot fluid inlet and outlet and the cooling fluid inlet and outlet. Many of these methods include tabs extending radially from a male member received in channels disposed axially within a female member. The tabs are further rotated in an annular groove of the female member thus locking the two members together.
U.S. Pat. No. 788,200 to Finch, issued Apr. 25, 1905, discloses a connection between a pipe section and a tubular sleeve for ordinary heating-stoves. The tubular sleeve comprises an interior annular groove and a plurality of interior longitudinal channels intersecting at their inner ends with the annular groove. The pipe section comprises exterior tabs corresponding to the longitudinal channels. The tabs are received in the channels and rotated into the annular groove to lock the pipe section and tubular sleeve together.
The U.S. Pat. No. 4,379,574 to Leichtl, issued Apr. 12, 1983, discloses a heat exchanger assembly, such as a radiator, including a filler spout extending from an opening in the assembly. The opening is formed with an inwardly extending skirt having a plurality of cam/lock sections. Each section comprises a receiving end, a leading surface, and a locking recess, defined by a stop. The opening includes a plurality of radial slots extending radially of the skirt and adjacent the receiving end of the cam surfaces. The opening further includes an annular sealing recess for receiving a seal. The spout comprises an upper portion having a radially extending shoulder and a lower portion having a plurality of radially extending tabs. The spout is inserted into the opening by passing the tabs through the slots. The tabs are received by the receiving end of the cam surface and as the spout is rotated in a counterclockwise direction, the tabs move along the cam surface until they snap into the locking recess and abut against the stop. The seal is compressed between the shoulder of the spout and the sealing recess in the opening to provide a fluid impervious connection.
U.S. Pat. No. 2,811,337 to Andersen, issued Oct. 29, 1957, discloses a heat exchanger comprising a shell having a first and second end defined by a flaring portion formed integral with a body portion of the tank. A first O-ring provides a seal between the flaring portion and a header within the tank. The assembly further includes caps connected to the ends of the tank and having inlet and outlet conduits. The caps include a rim having an annular flange and a shoulder. The flange abuts against the first O-ring to provide a seal between the body and cap and the shoulder abuts against the header to prevent axial movement of the cap. A retainer ring is seated in the flaring portion to connect the cap to the body of the tank and further prevent axial movement therebetween. A second O-ring provides a seal between the caps and the flaring portion.
U.S. Pat. No. 2,956,704 to Boni, Jr., issued Oct. 18, 1960, discloses a heat exchanger welded to a head barrel wall and including a tube inlet, tube outlet and head chamber. A tube sheet is positioned in the head chamber between the heat exchanger and the head barrel wall. A tube pass housing member is connected to a portion of the tube sheet and comprises an outlet elbow coupled to the tube outlet. The housing member and tube sheet are fixedly secured to the head barrel wall within the head chamber by a locking ring. The locking ring includes a bayonet type connection by including lugs engaging corresponding lugs on the barrel wall. A sealing ring is positioned between the tube sheet and the locking ring and compression screws engage the seal and compress it against the tube sheet and further lock the lugs together. The connection between the locking ring and the head barrel wall, however, does not allow for rotation of the locking ring relative to the tube sheet.
It remains desirable to provide a rotatable connection between an end cap and a tank of a heat exchanger, such that, the connection maintains a fluid impervious seal between the cap and the tank, yet allows rotation between the cap and the tank for orientation of the hot fluid inlet and outlet relative to the cooling fluid inlet and outlet. Further, such a connection is desirable to relax the tolerances required in manufacturing the heat exchanger and to reduce the effort in disassembling and repairing the heat exchanger. Further, such a connection is desirable to increase the heat transfer characteristics in the heat exchanger by using the cap members as fluid reservoirs to increase the capacity of fluid flow and heat transfer.